(a) Field of the Invention
The present invention relates to an improved structure of a transmission structure for an electrically operated bicycle, and more particularly to a transmission structure that is simple, output torque is large, and enables automatic switching between electrical operation and pedal operation, thereby enabling a bicycle to achieve effectiveness to easily move forward.
(b) Description of the Prior Art
In general, electrically operated bicycles of prior art use a design that separates the electric mechanism from the manual pedal mechanism, which separately actuate a rear wheel to achieve the objective of moving the bicycle forward. A shortcoming of such prior art structures is that a switching device must be provided between the electrical operating means and the pedal operating means to control interchange between the two mechanisms. Hence, prior art structures are more complex, and relatively inconvenient in use. Moreover, because of the separate disposition of the electric mechanism and pedal mechanism in prior art structures, thus, the electric mechanism portion is unable to function in coordination with a variable speed multiple sprocket chain wheel, and only enables providing the pedal mechanism with functionality of multistage speed change (as found on variable speed bicycles of prior art); Furthermore, when prior art structures meet an inclined roadway and there is insufficient electric drive torque, the pedal mechanism is unable to assist the electric mechanism to drive the bicycle forward. Accordingly, prior art structures fall short for practical use, and thus there are areas for improvement.
In light of the aforementioned shortcomings of transmission structures of prior art electrically operated bicycles, the inventor of the present invention, having accumulated years of experience in related arts, has meticulously carried out extensive study and exploration to ultimately design a new improved structure of a transmission structure for an electrically operated bicycle.